Petrol
As a lot of garden machinery is petrol powered, on occasions, petrol spills will happen. Do NOT therefore, fill on the lawn or near any plants for that matter. You will contaminate the soil and before anything will grow there again the contaminated soil will need removing and replacing. A lot of work for a minor lapse!
Hot Stuff
Anything hot (close to boiling or above) can kill the grass. A nice cuppa whilst sitting in the deck chair is a lovely way to relax. Put the cup down on the lawn whilst it’s still hot, and you may well leave a dead circle of grass! Be warned.
The same thing applies to power tools, such as hedge trimmers around the garden. They get hot and, if put down on the lawn, can quickly kill it.
Builders, Plasterers & Engineers
These guys, not all but some, have a tendency to swill buckets out on to the lawn. If the bucket contained mortar or plaster then there will be plenty of lime in it. If concentrated it can kill the lawn but even if it doesn’t it can contaminate the soil causing lawn problems for many years to come.
Other contactors use some pretty harmful materials and as they know flushing it down the drain is illegal they opt for dumping it on the garden.
Discuss this with them before you employ them; they won’t be offended.
Clothes Lines & Postman’s Short-cut
These can become well-trodden and worn, so before they get too bad, aerate to relieve the compaction. See How to Aerate the Lawn